A brisk walk each day for a minimum of 20 minutes could lead to considerable health benefits, according to a new study that suggests the sedentary lifestyle is responsible for twice as many deaths as obesity.

The good news is that even a modest amount of exercise could make a difference as long as it's regularly performed, say the researchers, whose study was published in the American Journal of Clinical Nutrition.

For an average of 12 years, the team measured height, weight and waist circumference against self-reported physical activity levels of 334,161 European men and women.

The benefits of adding a daily, 20-minute walk -- which burns between 90 and 110 calories -- were observed predominantly in subjects of normal weight, for they began to dwindle as subjects' body mass index (BMI) increased.

Just under a quarter, or 22.7 per cent, of subjects fit the research team's definition of inactive, staking no claims to recreational activity and holding a sedentary job.

For these individuals, the daily 20-minute walk would bump them one notch higher on the activity ladder, from inactive to moderately inactive.

According to the researchers this notch could be significant, reducing their chance of premature death by between 16 and 30 per cent.

An analysis of recent data on 9.2 million European deaths indicates that obesity is the culprit for 337,000 of them, yet 676,000 -- double that figure -- could be caused by lack of physical activity.

"This is a simple message: just a small amount of physical activity each day could have substantial health benefits for people who are physically inactive," says lead author Professor Ulf Ekelund from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge.

Dr. Ekelund does not, however, prescribe a moderately inactive lifestyle as a legitimate and reasonable goal.

"Although we found that just 20 minutes would make a difference, we should really be looking to do more than this -- physical activity has many proven health benefits and should be an important part of our daily life."

Hailing from the University of Cambridge, the research team sourced their data from the European Prospective Investigation into Cancer and Nutrition (EPIC) study.